Amphipoda Synopiüea. 25 



The habitus of the animal resembles a Lysianassa, the dorsal side 

 ul' tho bod}' being broad and even, without keel; the surface of the 

 body is smooth and hard as if polished. 



The jidult female. 



The head is much deeper than the pereion, broad, smooth; tho 

 rostrum is very broad at the base, slightly tapering towards the end, the 

 apex broadly rounded. The head with the rostrum is as long as deep, and 

 a little shorter than the first pereional segment. The insertion for the 

 antennae on the under-side of the head, at the base of the rostrum, 

 pointing to the case of the Oxycephalida^. 



The eyes occupy almost the whole sides of the head, separated 

 from one another only by a very narrow strip of the front; they con- 

 sist each of large oceUi, ranged in 18 longitudinal rows, 9 in the upper- 

 most row and 3 in the undermost one, in all about 100 ocelli in each eye. 



The first pair of antennœ [PI. Ill, fig. 42] are a third longer than 

 the head. The first joint of the peduncle is very thick and long, the 

 second very short, the third twice as long as the second. The flagellum 

 is 10-jointed; the first joint is as thick at the base as the last peduncular 

 joint, and is almost as long as all the following joints together (13: 15), 

 smooth, tapering anteriorly. The two following joints are short, equal, 

 a little narrower than the apex of the first joint; the last seven joints 

 are shorter and narrower, tapering towards the end, without hairs or 

 bristles. The secondary flagellum is three-jointed, almost as long as the 

 first joint of the ordinary flagellum; its first joint is very long and thick, 

 the two terminal very minute, carrying some minute hairs. 



The second pair of antennœ [PI. Ill, fig. 43] are much longer than 

 the first pair, reaching, if bent backwards, beyond the anterior margin of 

 the fourth pereional segment. The first joint of the peduncle is stout 

 and thick, projecting downwards into a short, round process, forming 

 the opening of a cavity in the joint; I suppose that the organ can be 

 interpreted either as an auditory cavity, as the lower, circular surface 

 of the process seems to be closed by a thin membrane, or as a secret- 

 ory gland. The dissection of the organ gives more probability to the 

 latter supposition, because the process is filled with a granular mass 

 and only a few very minute hairs are to be seen at the bottom of 

 the joint. The second and third joints are very short, but broad; 

 the fourth is the longest, broader than the fifth, carrying a single 



Nova Acta Reg. Soc. Sc. Ups. Ser. III. 4 



